The proposed investigation comprises an attempt to discover the relations between the child's spontaneous social-context speech and his pre-sleep monologue speech and an attempt to determine the role of pre-sleep monologues in the child's acquisition of his mother tongue. The data of concern will be obtained by sampling the spontaneous speech of two children weekly from a MLU of 2.0 to a MLU of 4.0, or for a minimum period of ten months. Both social-context speech and pre-sleep monologue speech will be sampled. The social-context speech samples will be compared with the pre-sleep monologue speech samples on a number of dimensions (including linguistic practice) in order to determine the relations between the child's speech in the two sampling contexts. These analyses of a longitudinal sample should clarify the role of pre-sleep monologues and linguistic practice in the child's acquisition of his native tongue.